In ozone generating systems that use as a source material, air or a nitrogen-added oxygen gas, to thereby generate ozone (O3) using an electric discharge, it is generally known that a nitrogen oxide (NOx) is produced as a byproduct in association with the generation of ozone. Further, because of being under ozone coexistence condition, the byproduct nitrogen oxide mostly exists in a form of dinitrogen pentoxide (N2O5). N2O5 has a physical property that is solidified at an ambient temperature under 30° C., so that there is a possibility that, under a normal operating condition, it adheres to almost all areas inside an ozone generating device as a discharge product.
Meanwhile, with respect to typical ozone generating systems, a periodic inspection per 3 to 5 years is recommended by the makers thereof. At that inspection, the system is suspended and further the ozone generating device is made open to atmosphere, so that a maintenance work to take out and clean up its electrode is performed. When the ozone generating device in a state with solid N2O5 adhering thereto, is made open to atmosphere, there arises concern that its metal member is corroded by nitric acid (HNO3) produced from a reaction of N2O5 with water in the atmosphere. This causes adherent materials to accumulate in the ozone generating device, which results in reduction of the ozone generation efficiency or results in choke-off in a pipe that provides an ozone generation space, so that it is difficult to maintain a stable operating state.
Thus, there are proposed: a method of handling an ozone generating device in which the tank of the ozone generating device, after it is kept heated using a water-heating device, is made open to atmosphere, to thereby remove N2O5 adhered inside the ozone generating device through vaporization (see, for example, Patent Document 1); and an ozone generator which includes means for purging inside the ozone generation device using an inert gas or a cleaning liquid (see, for example, Patent Document 2).